Airplane construction



June 21, 1932. T. p LEAMAN AIRPLANE GONST RUCTION Filed March 6, 1951 2 Sheets-Sheet 1 June 21, 1932. P. LEAMAN AIRPLANE CONSTRUCTION Filed March 6, 1931 2 Sheets-Sheet 2 Patented June 21, 1932 UNITED STATES new I Parana THOMAS P. LEAMAN, OF HEMPSTEAD, NEW YORK, ASSIGNOR T AMPHIBIONS, INC OF GARDEN CITY, NEW YORK, A CORPORATION OF NEW YORK AIRPLANE CONSTRUCTION Application filed March 6, 1931. Serial 1%. 520,491.

This invention relates to airplane construction, and has for an object to provide an improved construction by which the builder of airplanes can do away with the expensive and 5 difiicult tohandle duralumin now commonly employed in such structures;

It is also an object of the invention to provide a composite hull or fioat construction for flying boats or sea planes which may consist of a frame of tubular metal members with fabric covered sides and a solid bottom of metal, wood or composition.

Another object of the invention is to provide an improved means of making a watertight joint between the fabric covered sides and the solid bottom. 7

A further object of the invention is to provide an improved means for securing the tubular upper frame members to wooden chine stringers and floor timbers so that suchmem bers may be constructed of wood.

It is a special object of the invention to provide an improved reinforced fabric construction whereby such fabric can be used in numerous places in place of the expensive and difficult to handle duralumin or similar metal construction to thus reduce cost of manufacture and do away with the numerous objections of this metal construction.

With the foregoing and other objects in view, the invention consists in certain novel features of construction, combinations and arrangement of the elements as will be more fully disclosed in connection with the accompanying drawings.

In these drawings:

Fig. 1 is a top plan view of a portion of a flying boat showing it somewhat diagrammatically and with certain elements broken away to more clearly show. the construction;

Fig. 2 is a side elevation of the hull with a portion broke away to more clearly show the construction;

Fig. 3 is a bottom View of the hull with a portion broken away to more clearly show the construction;

Fig. 4 is a transverse section of a portion of the hull;

Fig. 5 is a detailed section on an enlarged scale taken transversely through one of the lower side portions of the hull;

Fig. 6 is a detailed side elevation showing the means for securing the frame to the chine, a portion of the bottom being shown in section; and

Fig. 7 is a vertical transverse section of the front or leading edge portion of an airplane wing construction showing how my improved reinforcement may be employed therein.

In the drawings my improved construction is shown as applied to a flying boat, that is an arrangement where thepilotand the passengers are in the hull itself, but it will of course be understood that it may be used for other types of airplane construction such as sea planes, in which the pilot and passengers are in a separate fuselage located above the float, and my improved reinforced fabric construction can be used practically at any location desired, and particularly to take the place of the expensive and difficult to handle duralumin or similar metals now generally employed for certain parts of the plane construction. This duralumin is notonly expensive and difficult to handle but is subject to rapid corrosion especially of salt water and electrolytic action. It is difficult to form to the proper shape, and also difiicult to fasten to secure watertight joints as it cannot be welded or soldered satisfactorily, and therefore must be fastened by riveting, and to make watertight joints it is necessary to use at least two rows of rivets.

As indicated on the drawings the hull indicated at 10 is of a frame construction composed principallyof a metal tubular construction which may includeupright tubular side members 11 and tubular metal diagonals or braces 12. Connecting the upper ends of these side members is a longitudinal gunwale stringer 13 extending longitudinally of the hull, and also of a metal tube welded to the uprights 11 and struts or braces 12. The frame may also include curved deck members lc'welded at their opposite ends to the gunwale stringers l3 and curved upwardly to give proper shape to the deck, and

' struction.

these deck members may be braced by frame members 15 also metal tubing welded to the various members. The frame may be stiffened by. the cross members 16 welded to the gunwale members, and this may be strengthened by upright central supports 17 mounted on the top of transverse floor timbers 18 by any suitable means such as inverted U-shaped bracket 19 straddling the floor timber and welded to it and gusset plates 20. Bracket 19 can be secured to the timbers by any suitable means such as transverse bolts 21. The joints between the members 11, 16 and 17 can be strengthened by suitable gussets 22 welded to these members as indicated at 9.

In the construction illustrated the side tubular frame members are secured at their lower ends to a longitudinally extending chine stringer 23 made of wood. and preferably at right angles to the chine to facilitate assembling and provide a strong rigid construction.v Extending transversely between these chine stringers on opposite sides of the hull are the floor timbers 18 which may also be of wood and suitably spaced as desired. I have provided improved means for securing together the tubular frame members, the chine stringers and the floor timbers. Thus there is provided a foot plate 24 having an upwardly extending tubular portion 25v'to receive the lower end of the upright tubular frame member 11, and to which this frame member is welded. The floor timber 18 is secured to this foot plate by an inverted substantially U-shaped gusset plate 26 straddling the upper edge of the timber and welded as indicated at 27 to the foot plate and the tubular portion 25. It may be secured to the floor timber by suitable transversebolts 28.

The diagonal members 12 can be welded to the tubular member 25 and the gusset 26 as indicated at 29. This whole construction can be secured to the chine 23 by means of the bolts 30 giving a very strong rigid con- The transverse floor timbers 18 can be stiffened by longitudinal stringers 31 recessed into the lower edge of the timbers and provide with the timbers a strong rigid supporting structure for the solid bottom 32 of any suitable material. This bottom may be of metal, wood or a composition such for example as, a heavy fabric molded in bakelite or other phenolic condensation product.

At the present time it is common practice to cover the sides and also the bottom with duralumin as this is of comparatively light weight and is supposed to have better corrosive resistance properties than some of the other metals. A particular use is along the lower parts of the side wall below and to a certain distance above the water line to protect the hull against beating of the waves and particularly floating objects. This duralumin, however, is very expensive and dif-' ficult to handle especially to properly shape on the job and furthermore is not sufliciently corrosive resistant to salt water and electrolytic action. Furthermore, as it cannot be welded or soldered satisfactorily it must be riveted and thus it is difficult to make watertight joints.

I have overcome these difliculties with an improved bottom construction, and improved reinforced fabric construction. lVith the floor timber and stringer construction 18 and 81 and with a solid bottom 32, a very rigid and strong bottom construction can be secured, and this permits the use of a solid bottom 32 of various materials such as metal, wood and the composition construction of heavy fabric molded in a phenolic condensationproduct. This latter gives an especially strong and tough construction as compared with its weight. g

, For the reinforcement for the sides of the hull or float below and to a certain distance above the water line Ihave provided animproved reinforced fabric construction which permits covering the sides and other sufaces of the hull or float-with fabric which is better and less expensive than the old duralumin construction. This reinforced fabric is composed of two or more thicknesses of a suitable fabric 83 and 34 such for example as heavy canvas. These heavy woven fabric members are stitched together bylongrtudinal seams 35 spaced laterally from each other at suitable distances to provide longitudinal pockets or hems 36, and inserted in these pockets or hems are reinforcing and strengthening members or stringers 3 7. These are preferably rods or tubes, the tubes being preferred as they give greater strength for a given weight of material, a satisfactory element being stainless steel tubes. These tubes effectively strengthen and reinforce the fabric providing a strong durable waterproof double fabric constuction in which should the outer thickness of fabric be punctured there is still a protected waterproof inner fabric which effectively prevents water leaking into the hull. The fabric below the reinforcement is wrapped under the chine stringer 23 as indicated at 38 and may be tightly clamped between this chine and the solid bottom 32 by the means for securing the bottom to the chine such forinstance as the screws 39. Thus this fabric is tightly clamped between the chine and the bottom and makes a very effective waterproof oint without difficulty.

This reinforced fabricv may be extended to any height desired, and preferably there is a filler block 40 between this reinforcement and the frame members 11 and 12 to form a backing for the covering. The fabric covering 33 may be extended upwardly over the deck as shown in Fig. l, and may be secured to the frame members by any suitable means such as fairing strips 41 fastened on the inner side of the fabric and connected to the members of the frame by suitable connectors 42.

It will, of course, be understood that this reinforced fabric construction can be used at any location desired. It is shown in Figs. 4 and 5 as being located at the lower part of the outer side walls below and to some distance above the water line, but this is merely by way of illustration, and it may be located in any position desired such for example as the bottom of the hull or float or the top wall of the deck as indicated at 43 in Fig. 1. The extent of the reinforcement longitudinally of the hull at the side thereof is indicated by the dotted lines 52 in Fig. 3.

Another illustration of a use for this re inforced fabric is shown at Figs. 1 and 7. Here it is shown as being used for reinforcing the upper and lower walls of the wing construction at its leading edge. A section of the front portion of the wing is shown in Fig. 7, the part shown including the front spar 44 of wood and the nosing 45 may also be of wood. Between the two is the usual framing 46 including the nose trusses 47. A common covering for this leading edge construction at the present time is duralumin, but as indicated above this is expensive and difiicult to handle. These wing surfaces can be very effectively covered and protected by my improved reinforced fabric. Thus this reinforced fabric can be secured on the frame construction 45, 46 on the upper side thereof as indicated at 48 with the rods 37 extending longitudinally of the wing, and similar reinforced fabric can be placed on the underside as shown at 49 with the intermediate two or more thicknesses of fabric folded over and covering the nosing 45 as indicated at 50. Then, the whole construction can be covered with the doped fabric 51 placed outside the reinforced fabric 48 and 49, and also over the fabric 50. This forms a very strong and durable wing covering construction which can be placed in position without difficulty and easily made to form to the shape of any wing section desired.

It will be seen from the above that I have provided an improved hull and float construction and also a greatly improved fabric construction which can be used for protecting any desired surface of the hull or float or other parts such as the wings if desired.

Having thus set forth the nature of my invention. what I claim is:

1. In an airplane construction, a hull or float including a frame formed of metal tubing, fabric side coverings, means on the inner sides of said coverings for securing them to the frame, and a solid bottom connecting the lower sides of the frame with the fabric sides extending inwardly under the sides of the frame and between the frame and the bottom.

2. In an airplane construction, a hull or float comprising a frame including longitudinal chine stringers at the lower edges of the sides of the frame, a fabric covering secured to the sides of the frame and folded inwardly under said chine stringers, and a solid bottom secured to said stringers below the folded in portion of the fabric covering.

3. In an airplane construction, a hull or float comprising a frame including longitudinal chine stringers at the lower edges of the sides of the frame, transverse floor timbers extending between the chinestringers a fabric side covering secured to the frame and folded inwardly under the stringers, and a solid bottom secured to the-timbers and the stringers and clamping said inturned portion of the fabric covering betweenthe stringers and the bottom. I

4. In an airplane construction, a hull or float including a frame having its upper and side portions of metal tubing and longitudinal wooden chine stringers along the lower edges of the side portions, wooden timbers extending transversely between the chine stringers, a foot plate having a tubular portion extending upwardly therefrom to receive the lower ends of the tubular frame members, gusset plates secured to said tubular portion and a transverse timber, and means for securing the foot plate to the chine stringer.

5. In an airplane construction, a hull or float comprising a frame having side portions including upright metal tubular members, a longitudinal wooden chine stringer at the lower edge of each side portion, a foot plate secured to the chine stringer and having an upright tubular portion to receive the lower end of the upright frame member, transverse timbers extending between the chine stringers, and a gusset plate welded to the upright tubular portion of the foot plate and securedto a cross timber.

6. In an airplane construction, a hull or float comprising a frame having side portions including upright frame members, a longitudinal chine stringer at the lower edge of each side portion, the uprightmember being at substantially right angles to the chine, and a foot plate secured to the chine and having an upri ht tubular portion to receive the upright frame member and connect it to the chine.

7. In an airplane construction, a hull or float comprising a frame having upright side portions, a fabric covering secured to the side portions having a plurality of longitudinal pockets, and stringers in said pockets extending longitudinally thereof and forming a reinforcement for the fabric covering.

8. In an airplane construction, a hull or float comprising a frame having upright side portions, a fabric covering secured to the side portions including two or more thicknesses of fabric stitched together at laterally spaced longitudinal seams providing a plurality of longitudinal pockets, and longitudinally extending stringers in said pockets forming a reinforcement for the fabric.

9. In an airplane construction, a hull or float comprising a frame having upright side portions, a longitudinal chine stringer at the lower edge of each side portion, a fabric covering secured to the side portions including two or more thicknessesof fabric stitched together by laterally spaced longitudinal seams providing a plurality of longitudinal pockets, longitudinally extending stringers in said pockets providing reinforcement for the fabric, and a solid bottom secured to and extending between the chines, the fabric below the reinforcement being folded under the chine and secured between the chine and bottom. 7

In testimony whereof I afiix my signature.

THOMAS P. LEAMAN. 

